1. Field of the Invention
This invention relates to a starting control valve assembly in a multiple throttle of a multiple cylinder engine for a vehicle such as a motorcycle.
2. Description of Related Art
In a multiple throttle valve body of a multiple cylinder engine for a motorcycle, etc., as shown in FIG. 6 and FIG. 7, a starter valve 3 is provided for each throttle body 1, and the inside of an air cleaner 4 is connected through these starter valves 3 to intake ports 5 of throttle bodies 1.
The starter valve 3 is formed in the throttle body 1, and has tuning screws 3a, 3b provided midway along a flow path connected to the intake port 5. Valves provided on the tips of the tuning screws 3a are moved by rotating the tuning screws 3a. One of the tuning screws 3b constitutes a reference among the tuning screws 3a, 3b. Adjustment of the degree of idle opening between each cylinder is carried out by adjusting the degree of opening of the flow paths, and adjusting the amount of intake from the air cleaner 4.
Furthermore, the starter valves 3 are provided with lever plates 6 respectively engaged with the tuning screws 3a, 3b. The lever plates 6 are attached to a support shaft 7 which is supported rotatably and urged by a spring 8. A wire drawn from a choke is connected to one of the lever plates 6. When the engine is started, the lever plate 6 is rotated backwards against the force of the spring 8. The axis of the support shaft 7 acts as a center, by pulling the wire. In this way, each of the tuning screws 3a, 3b of each of the starter valves 3 are collectively rotated towards the rear, and the intake amount of the intake ports 5 is increased.
When the intake amount is increased at start up, the above described starter valves 3 are simultaneously rotated towards the rear. Therefore, there is a need for a connecting structure so that the tuning screws of each of the starter valves 3 can slide together. This increases the number of components and brings about an increase in the cost.
Also, there is a simple structure for distributing air from one valve to the intake ports of each throttle body at the time of idling and start up. However, in this case, competition for air supply occurs between the cylinders which causes a usage limitation and a uniform amount of air can not be supplied.